Light intensity indicator



Dec. 7. I937. 5, woon's 2,101,122

LIGHT INTENS ITY INDICATOR Filed March 8, 1955 3 Sheets-Sheet 1 37 lJaa. a. 11/002505 I00 41/ BY ATTORNEY Dec. 7, 1937.

C. S. WOODSIDE LIGHT INTENS IT Y INDICATOR Fil ed March a, 1955 sSheets-Sheet 2 if Huh, unmmm .Hmmrmmmh.h,

ATTORN Dec. 7, 193 7.

c. s. WOOD SIDE LIGHT INTENSITY INDICATOR Filed March 8, 1935 5Sheets-$heet 3 un, I II M ATTORN Patented Dec. 7, 1937 UNITED STATESLIGHT INTENSITY INDICATOR Cornelius S. Woodside, Verona, N.J., assignor,

by mesne assignments, to Westinghouse Electric and ManufacturingCompany, East Pittsburgh, Pa., a corporation of Pennsylvania ApplicationMarch 8, 1935, Serial No. 9.991

5 Claims.

This invention relates to a device for making visible determinations ofvariations in the intensity of light and more particularly to'a devicewhereby an incandescent lamp of a selected wattage may be employed todetermine the proper wattage lamp to be used to produce a selectedintensity of light.

It has been found that the average person using incandescent lamps,particularly when such lamps are in an elevated fixture, as for exampleone of the bridge lamp type, finds it difficult to determine the properwattage lamp to be used to give the correct intensity of light for thepurpose intended, as for example for reading.

It is the desire of the lamp manufacturer as well as the distributors tofurnish lampsgiving sufficient light for the purpose intended and toalso aid the customer in avpiding the use of lamps which give anexcessive amount of light with the added expense of current. consumed.

Furthermore, it is desirable to furnish a purchaser with a lamp ofsufiicient wattage to avoid eye strain.

The present invention, therefore, relates to a portable device which maybe used in connection with the saleof standard lamps and consists of ahousing in which an incandescent lamp of a selected wattage is disposed.The housing is provided with a light-receiving surface and between thesurface and the lamp is disposed an adjustable diaphragm which variesthe intensity of the light so that the purchaser may examine a page ofreading matter with light of different intensities and determine whichintensity of light is most suitable for the individual need.

' In the construction herein provided a sheet of translucent orlight-diffusing material is disposed between the lamp and theilluminated surface.

Means are provided for varying the light transmitting area of. the lightdiffusing material which means are so arranged and adjustable that thedegree or intensity of light passing through the translucent medium isindicated by a measurement in the form of the wattage of the lamp,which'under the reading conditions in which the lamp is to be used willgive such intensity.

It is an object of the present invention, therefore, to provide a simpleand effective device for determining the particular wattage lamp to beused under predetermined conditions.

Another object of the invention is to provide a convenient portablelight intensity indicating apparatus so arranged and constructed that agiven light intensity will be indicated or represented by reference to'a given wattage lamp.

A further object of the invention is to provide a light indicatingmeasuring device in the form of a foldable housing which may be easilydisassembled for shipment and quickly and conveniently assembled foruse.

Other objects and advantages of the invention will be more clearlyunderstood from the following description, together withthe-accompanying .drawings in which:

Fig. 1 is a perspective view of the apparatus in position for operation;

Fig. 2 is an enlarged vertical sectional view taken on the line II-II ofFig. 1;

Fig. 3 is a sectional view taken on line III-III in Fig. 2, looking inthe direction of the arrows;

Fig. 4 is a perspective view of the several parts of the apparatusshowing a lower frame removed and indicating, in dotted lines, thehousing folded or knocked down preparatory to storage or shipment;

Fig. 5 shows the platform, or the part forming Fig. 6 shows the entirestructure packed and a container.

The selected embodiment of the invention may, as shown, comprise afoldable housing In having a rectangular base or supporting frame 11.The housing is provided with a light-receiving surface l2 which isdisposed at a convenient angle for observation. Above the surface l2 isa partition 13 and a platform 14 having a plurality ofapertures I6. Asheet of translucent or light-diffusing material I1 is disposed beneaththe platform covering the apertures 16. The apertures 16 are in the formof sectors and a. disk I8, pivoted at 19 on the platform, is providedwith apertures 2|, similar to the apertures 16, and arranged to coincidetherewith upon adjustment of the disk about its pivot. A hand piece 22is provided for adjusting the disk.

An incandescent electric lamp 22' may posed in the upper portion orlight housing 23, an aperture 24 being provided to receive the lampsocket. When the lamp is lighted, light rays are transmitted through thetranslucent material l1, and the disk l8 may be adjusted to permit thebe disapertures 16 to be fully exposed and transmit the maximum amountof light or the disk may be I rotated to cut down the amount of lightpassing through the translucent material. Thus the intensityof the lightfalling on the surface 12 is varied. A sheet of reading matter 23' orother seeing task may be placed on the surface l2 and.

through a slot 28 in the wall 25, and the marks 21 indicating thevarious wattage lamps are calibrated. As the disk is turned the lightintensity is varied. The light falling-on the surface 12 will have theintensity of the lamp indicated when the marker on the hand pieceregisters with the marking line indicating a particular wattage lamp.

It is to be understood that the lamp selected for use in connection withthe present device may be of a predetermined wattage as for example a60-watt lamp may be used and the light intensity measured with diiferentpositions of the disk of diaphragm to obtain the marks representing thedifferent wattage lamps.

The present device is used to determine the proper intensity of lightfor lamps which are positioned a considerably greater distance from theuser than the distance between the light receiving surface I2 and thelamp 22. Thus, if the distance at which a lamp is to be used is fromthree to four feet from the surface illuminated it will be evident thatby means of the present device a lamp of 60 watts, for example, may beemployed to indicate the intensity of light obtained from a or watt lampat a greater distance.

The present invention provides a portable structure which consistsessentially of the frame i i and the part providing the removablesurface l2. The frame is provided with ears 3| for insertion into slots32. The part with the surface I2 is provided with a lower flap 33 whichmay be inserted between an inclined floor 34 and an outer side 35 of theframe. The platform I3 is provided with side flaps 36 which may beriveted to the side walls 31 and 38 of the housing, and the front wall25 of the housing is foldable and provided with a cut-out portion 39which, in conjunction with the platform [3, provides the slot 28 toallow for movement of the hand piece of the disk.

An extension flap 4| may be provided on the portion M to receivedescriptive or advertising matter. A rear wall 42 is provided for thelight chamber 23, which wall is provided with flaps for retaining it inposition.

When it is desired to ship the device, the frame II and the surfaceelement l2 may be removed. The walls 25 and 42 may then be foldedinwardly beneath the top wall of the housing and the housing collapsedas shown in dotted lines. It

. is particularly applicable to lamps sold under the trade name Mazda:

Although a preferred embodiment of the invention is shown and describedherein it is to be understood that modifications may be made thereinwithout departing from the spirit and scope of the appended claims. Whatis claimed:

1. A light intensity indicator comprising a housing having an upperchamber with a closed front wall, a lower chamber with a large frontopening, a light source in said upper chamber, a member in said lowerchamber adapted to receive light from said upper chamber and support a se e i ng task for inspection through said opening, means between saidchambers and movable intermediate said light source andsurface forvarying the intensity of light illuminating said surface, and meansindicating the degree of intensity of light falling on said surface orseeing task in terms of lamp wattage.

2. A light intensity indicator comprising a housing having an upperchamber with a closed front wall, a light source received therein, saidhousing also having a lower chamber with a large front opening, a memberin said lower chamber adapted to receive light from said upper chamberand support a seeing task for inspection through said opening, a wallseparating said chambers, apertures in said wall, a light-diffusingmaterial over said apertures, an opaque member movable over saidapertures to vary the intensity of light from said upper chamber fallingon said surface, and means for indicating the intensity of the light onsaid surface in terms of lamp wattage,

3. A light intensity indicator comprising a housing having an upperchamber with a closed front wall, alight source in said chamber, a lowerchamber in said housing and provided with a large front opening, and amember having a light receiving surface, and adapted to support a seeingtask for inspection through said opening, a

wall separating said chambers, apertures in saidwall, light diffusingmaterial over said apertures,v

an opaque member movable over said apertures to vary the intensity oflight from said upper chamber falling on said surface, and means formoving said member, said means indicating the wattage of a lamp giving asimilar intensity of light under selected conditions.

4. A light intensity indicator comprising a housing having an upperchamber with an opaque front wall, an incandescent electric lamp of agiven wattage in said chamber, a lower chamber in said housing andprovided with a large front opening, a wall in said lower chamberproviding an upper surface receiving light from said upper chamber andadapted to support a seeing task for inspection through said opening, apartition dividing said chambers, a plurality of radially disposedapertures in said partition, light translucent material closingsaidapertures, a disc having radial apertures corresponding to saidpartition apertures and separatedby opaque sec-. tions, means forrotating said disc to cause the opaque sections to vary the effectivelight transmitting areaof said partition apertures to correspondinglyvarythe intensity of light falling upon said surface or seeing task, andmeans for indicating the intensity of said light in terms of lampwattage.

5. A light intensity indicator comprising a housing having an upperchamber with a light excluding front wall, an incandescent electric lampof a given wattage in said chamber, a lower chamber in said housing andformed with a large front opening, a wall in said lower chamberproviding an upper surfacereceiving light from said upper chamber andadapted to support a seeing task for inspection throughsaid opening, apartition dividing said chambers, a plurality of radially disposedapertures in said partition, light translucent material closing saidapertures, a disc having radial apertures corresponding to saidpartition apertures and separated'by opaque sections, and means forrotating said disc to move said opaque sections to close the partitionapertures to. a greater or less degree and vary the intensity of lightpassing therethrough and falling on said surface.

CORNELIUS S. WOODSIDE.

